Please help help please

This question is incomplete, the complete question is;

A certain liquid X has a normal boiling point of 150.4 °C and a molar boiling point elevation constant kb is 0.60 °Ckgmol⁻¹.

A solution is prepared by dissolving some urea (NH22CO) in 750 g of X. This solution boils at 150.9 °C . Calculate the mass of urea that was dissolved. Round your answer to 3 significant digits.

Answer:

the mass of urea that was dissolved is 37.5 g

Explanation:

Given the data in the question;

normal boiling point of X; Tb⁰ = 150.4 °C

boiling point of solution Tb = 150.9 °C

Change in boiling point Δt = Tb - Tb⁰  = 150.9 °C - 150.4 °C = 0.5 °C

Kb = 0.6 °C.kg.mol⁻¹

V = 750 g

Now, we know that

Δt = Kb × molality

so

0.5 = 0.6 × molality

molality = 0.5 / 0.6

molality = 0.833

we know that molar mass of urea is 60 g/mol

so

molality = mass × 1000 / molar mass × volume( g )

we substitute

0.833 = ( mass × 1000 ) / ( 60 × 750 )

0.833 = ( mass × 1000 ) / 45000

0.833 × 45000 = mass × 1000

mass = ( 0.833 × 45000 ) / 1000

mass = 37485 / 1000

mass = 37.485 ≈ 37.5 g   { 3 significance figure }

Therefore, the mass of urea that was dissolved is 37.5 g

Answer:

Option b.

Al < B < P < N

Explanation:

Electronegativity is the capacity of an atom to attract electrons.

Usually, if we look at the periodic table, the elements in the left are the ones with the least electronegativity, and as we go to the right, the electronegativity increases (this is not really exact)

There are a lot of tables of electronegativity that can be used here, we can find that:

element:    electronegativity:

    N                         3.04

    B                          2.04

    P                          2.19

    Al                          1.61

So, the order from least to greatest is:

Al, B, P, N

Then the correct option is:

b: Al < B < P < N

Answer:

-46.67 J.

Explanation:

We are given;

Initial Pressure = 15atm = 15 × 10^(3) J

Final pressure = 1atm = 1 × 10^(3) J

Temperature = 300k

The pressures were converted to Joules.

Formula for the entropy change is;

∆S_system = ∆S_surrounding = -(dQ)/T

-(dQ)/T = (-(15 × 10^(3)) - (1 × 10^(3))/300)

= -46.67 J.

Answer:

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Explanation:

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Answer:

the answer is D .................

The question is incomplete, the complete question is;

Suppose 0.377g of potassium acetate is dissolved in 250.mL of a 57.0mM aqueous solution of ammonium sulfate.

Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.

Round your answer to 3 significant digits.

Answer:

0.0152 M

Explanation:

The equation of the reaction is;

2CH3COOK(aq) + (NH4)2SO4(aq)------> K2SO4(aq) + 2CH3COONH4(aq)

Number of moles of potassium acetate = 0.377g/98.15 g/mol = 0.0038 moles

Number of moles of ammonium sulphate = 250/1000L × 57 × 10^-3 = 0.014 moles

2 moles of potassium acetate yields 2 moles of ammonium acetate

Hence;

0.0038 moles of potassium acetate yields 0.0038 moles of ammonium acetate

Also

1 mole of potassium sulphate yields 2 moles of ammonium acetate

0.014 of potassium sulphate yields 0.014 × 2/1 = 0.028 moles of ammonium acetate

So potassium acetate is the limiting reactant.

Since 0.0038 moles of ammonium acetate is produced, the final concentration of potassium acetate is = 0.0038 moles of ammonium acetate/0.25L = 0.0152 M

Hence final concentration of acetate ions =0.0152 M

Answer:

How many stereoisomers are possible for CHCl3 provided that the central carbon has tetrahedral geometry?

Explanation:

The stereoisomers are the molecules with the same molecular formula but the different spatial arrangements of atoms around the central atom.

For the given molecule, [tex]CHCl_3[/tex]

only one spatial arrangement is possible.

Hence, one stereoisomer is possible.

It is shown below:

Answer: See explanation

Explanation:

The explanation for why solid sodium chloride can't conduct electricity while molten sodium chloride can is explained below:

Ionic compounds that are in their solid state like sodium chloride have their ions fixed in position. Due to this reason, the able to move, therefore we can say that the solid ionic compounds cannot be able to conduct electricity.

On the other hand, ionic compounds in their molten state, are free to flow unlike when they're in their solid state and therefore we can say that molten sodium chloride can be able to conduct electricity.

Answer:

See explanation and image attached

Explanation:

Thiocyanic acid is made made up of hydrogen, sulphur, carbon and nitrogen atoms. Carbon is the central atom in the molecule.

The molecule has a total of sixteen valence electrons as shown in the image attached. There are no formal charges in the structure of the molecule as shown.

The molecule is linear in shape.

Answer:

A person doing physical work needs lots of good carbohydrates to keep their energy levels up and proteins to repair a muscle that might get wear and tear from overexertion. Carbohydrate will help the person work for more extended periods.

Answer:

option a

hope helps you

have a great day

Answer:

Mass CO2 = 3.75 grams

Mass H2O = 2.30 grams

Mass SO2 = 2.73 grams

Explanation:

Step 1: Data given

Density of Liquid ethyl mercaptan, C2H6S = 0.84 g/mL

Volume of ethyl mercaptan = 3.15 mL

Step 2: The reaction

2C2H6S + 9O2 → 4CO2 + 6H2O + 2SO2

Step 3: Calculate mass of ethyl mercaptan

Mass = Volume * density

Mass ethyl mercaptan = 3.15 mL * 0.84 g/mL

Mass ethyl mercaptan = 2.646 grams

Step 4: Calculate moles ethyl mercaptan

Moles = mass / molar mass

Moles ethyl mercaptan = 2.646 grams / 62.13 g/mol

Moles ethyl mercaptan = 0.04259 moles

Step 5: Calculate moles of other products

For 2 moles ethyl mercaptan we need 9 moles O2 to produce 4 moles CO2, 6 moles H2O and 2 moles SO2

For 0.04259 moles we need 0.1917 moles O2 to produce:

2*0.04259 = 0.08518 moles CO2

3*0.04259 = 0.1278 moles H2O

1*0.04259 = 0.04259 moles SO2

Step 6: Calculate mass produced

Mass = moles * molar mass

Mass CO2 = 0.08518 moles * 44.01 g/mol

Mass CO2 = 3.75 grams

Mass H2O = 0.1278 moles * 18.02 g/mol

Mass H2O = 2.30 grams

Mass SO2 = 0.04259 moles * 64.07 g/mol

Mass SO2 = 2.73 grams

Answer:

isn't it 0.998

Explanation:

cause 0.998 is in the same grams / mole. I don't get

A calorimeter has been filled with 75 mL of water. The number of grams of water is 74.85 grams.

A calorimeter is an instrument that is used to measure calorimetry. It is used to measure the heat of chemical reactions and physical and chemical changes.

Mass is the quantity of matter in a physical body. Volume is the space occupied by a three-dimensional object. Mass is the quantity of matter in a physical body. The product of the compound's molar mass and the substance's moles are defined as mass.

Given, that the volume of the water is 75 mL

The temperature of the water is 25 °C

The density of water is 0.998 g/mL

To calculate the mass, the volume is multiplied by density.

Mass = volume x density

putting the values in the formula

75 x  0.998 = 74.85 grams

Thus, the grams of water that have at 25°C is 74.85 grams.

To learn more about density, refer to the link:

https://brainly.com/question/26304205

#SPJ2

The question is incomplete, the complete question is:

A chemist measures the amount of iodine solid produced during an experiment. He finds that 8.31 g of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to the correct number of significant digits.

Answer: The number of moles of solid iodine produced is 0.0327 moles

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of solid iodine = 8.31 g

Molar mass of solid iodine = 253.8089 g/mol

Plugging values in equation 1:

[tex]\text{Moles of solid iodine}=\frac{8.31g}{253.8089g/mol}=0.0327mol[/tex]

Hence, the number of moles of solid iodine produced is 0.0327 moles

Answer:

heat; temperature; surrounding; insulated.

Explanation:

A calorimeter can be defined as a scientific instrument or device designed and developed for measuring the heat involved in reactions or other processes, especially by taking the measurement of the temperature of the materials surrounding the process.

Basically, a calorimeter is insulated using materials with very high level of resistivity so as to prevent heat transfer to the outside of the device (calorimeter). Some of the components that make up a simple calorimeter are thermometer, an interior styrofoam cup, an exterior styrofoam cup, cover, etc.

Additionally, a calorie refers to the amount of heat required to raise the temperature of a gram of water by one degree Celsius (°C).

Answer:

because the have stronger electrostatic force

Answer: The property of all bases is that they are substances which neutralizes an acid to form a salt and water only.

Explanation:

A base is also s substance that can accept or combine with a proton; a proton acceptor.

Bases include the oxides, hydroxides and carbonates of metals. These include MgO,Na2O, NaOH,Ca(OH)2. Most metals burn in oxygen to form metallic oxides which are basic. Examples are the MgO and Na2O.

Other properties or characteristics of bases includes:

--> They have a bitter taste.

--> They turn red litmus paper blue.

--> They are soapy to touch.

--> Aqueous solutions of bases are also electrolytes. Bases can be either strong or weak, just as acids can.

Bases (sodium hydroxide) can be used in the preparation of soaps, glass, paper and rayon. While some bases (magnesium hydroxide) can also be used to manufacture toothpaste and laxatives.

Answer:

NH4Cl > Li2SO4 > CoCl3

Explanation:

Let us recall that the freezing point depression depends on the molality of the solution and the number of particles present.

Let us also recall that freezing point depression is a colligative property. It depends on the number of particles present in solution.

Usually, the more the number of particles present, the lower the freezing point. Hence, NH4Cl which has only two particles will have the highest freezing point while CoCl3 which has four particles will have the lowest freezing point.

Answer:

1) incorrect

2) incorrect

3) correct

4) correct

5) correct

6) incorrect

Explanation:

The correct electronic configuration of chromium is; [Ar] 3d⁵ 4s¹

The correct electronic configuration for Zr is; [Kr] 4d² 5s²

The correct electronic configuration of Cu^+ is; [Ar] 3d¹⁰

The electronic configuration of an atom refers to the arrangement of electrons in the atoms of such element.

The appropriate number of electrons and its properly written electronic configuration is clearly shown in this answer.

Answer:

A) habitat

Explanation:

a habitat is essentially the organisms "home". also known as a "niche"

Explanation:

here is the answer to your question.

Answer:

0.518 g

Explanation:

Step 1: Write the balanced equation

3 CaCl₂ + 2 H₃PO₄ ⇒ Ca₃(PO₄)₂ + 6 HCl

Step 2: Calculate the moles corresponding to 0.555 g of CaCl₂

The molar mass of CaCl₂ is 110.98 g/mol.

0.555 g × 1 mol/110.98 g = 5.00 × 10⁻³ mol

Step 3: Calculate the moles of Ca₃(PO₄)₂ produced

5.00 × 10⁻³ mol CaCl₂ × 1 mol Ca₃(PO₄)₂/3 mol CaCl₂ = 1.67 × 10⁻³ mol Ca₃(PO₄)₂

Step 4: Calculate the mass corresponding to 1.67 × 10⁻³ moles of Ca₃(PO₄)₂

The molar mass of Ca₃(PO₄)₂ is 310.18 g/mol.

1.67 × 10⁻³ mol × 310.18 g/mol = 0.518 g

Answer:

The Density Of Ar (g) At -11°C And 675 MmHg (R =0.08206 L·atm/mol·K, 1 Atm = 760mmHg).

Answer:

photoelectric effect, phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a metal plate when light falls on it.

Answer:

Deductive reasoning